I would have to suggest Deus Ex, or perhaps Vampire: The Masquerade - Bloodlines. Both games offer so much replayability, some of the best dialogue in games ever and Vamp offers a fascinating and dark story.

Some dweebs say Deus Ex is bad since you can't just shoot everything, unless you put skill points into the "Shooting stuff" skill, and people complain that the graphics are bad. But really, the people that are put off that easily don't deserve to play the magnificence that is Deus Ex. Vamp is buggy as hell, but download the latest fan-made patch, and enjoy one of the most sophisticated game stories ever written.

This is going old school: ANY Black Isles RPG (especially Planescape: Torment), Doom series, System Shock series, Thief series, Diablo 1 and 2, and most importantly, any of the LucasArts SCUMM based adventure games from the 90's.

That's a very subjective question. Personally the PC games that I think are the best are "old school" games that even go as far back as the DOS era. Looking at what people have said so far, I tend to disagree with the games that are current by today's standards if they belong to a series that has been around for a long time. What I mean is, when people say Fallout 3 is the best I highly disagree and will say that the best is still Fallout 1 and 2 (although New Vegas is pretty good and even better than FO3). When people say Starcraft 2 is the best, again I disagree and have to say that the original Starcraft is better. Maybe it's just the nostalgic value and the fact that I still enjoy playing the heck out of the old PC games I have. But anyways, aside from mentioning the old Fallout games, I've found myself playing a lot of Neverwinter Nights and Neverwinter Nights 2, Baldur's Gate, Icewind Dale, and Arcanum. I really like Arcanum and would recommend it to anyone who likes Steam Punk fantasy games or even Fallout.

You bring up some very good points especially about the open ended part of the question. I dont think you can fault people though for liking Fallout 3 over the first 2. Although they are under the same name one is basically a FPS and the originals were turn based RPG/Strategy games.

I would question you about StarCraft 2. I would say that at the time I enjoyed the original over SC2. It changed the RTS genera for most everything that followed. However by today's standards I can barley go back and play it. The terrible pathing of units, limited squad count, rough AI, and then it just looks bad.

So for when it was released compared to similar games in its era SC was better then SC2. However I would say SC2 is a better game than SC, again by today's standards.

Man if I had to pick some games to argue as best PC of all time, that is rough. Anything from Blizzard. Battlefield 2 was amazing for its time. The CIv games especially 4. Unreal, with its amazing bot/mp matches. Oblivion. Plus 2 of my old favorites that really need to be brought back Tie Fighter, and MechWarrior 2

I might be wrong on this, but I think that also has a lot to do with the current generation of gaming just being over-saturated with FPS games. I can especially understand why people would like FO3 if they never really played the old games first, or if for whatever reason they just didn't get into the older games.

I see your point, but for me I don't really have that kind of problem. I think on my part it also has to do with how my library of current generation of games is extremely small. I just don't have much interest in what's currently hot on the market and still find myself going back to playing older games just as easily. Although maybe it's just more so because of nostalgia.